1. Field of the Invention
The invention relates to flash analog-to-digital converters (ADCs), and more particularly to a flash ADC with a plurality of interpolators.
2. Description of the Related Art
Currently, analog-to-digital converters (ADCs) are widely used in a variety of applications, such as medical systems, audio systems, test and measurement equipment, communication systems, and image and video systems, etc. The most common ADC construction comprises flash ADCs, pipeline ADCs and successive approximation register (SAR) ADCs, wherein the flash ADC and the pipeline ADC are faster than the SAR ADC.
High-speed and low-resolution flash ADCs are widely used in current circuit systems, such as disk drive read channel, DVD playback, and communication receiver systems. In general, the number of comparators required to construct conventional flash ADCs is exponentially related to the number of bits of the conventional flash ADCs. For example, the conventional flash ADC with N-bits of resolution requires 2N−1 comparators. Thus, an N-bit flash ADC has 2N−1 comparators, arranged in cardinal order to compare the same input signal against a respective cardinal order of 2N−1 equally spaced reference voltages. However, each comparator will occupy a larger chip area
Therefore, a flash ADC with a plurality of interpolators is desired to decrease the number of comparators required.